Apple has released the first beta of OS X Mavericks 10.9.1 to developers. Apple has asked developers to focus their testing on Mail, Graphics Drivers and VoiceOver. When released to the public, OS X Mavericks 10.9.1 will be the first incremental update to Apple's new operating system. Since its roll out in October, Mavericks has only seen a minor update that fixed a problem with Mail. There are no known issues with the first beta of OS X Mavericks 10.9.1, which is labelled build 13B27, but it's not yet known when Apple will release the update to the public. See also: OS X Mavericks tips and tricks, how to do everything in Mac OS X 10.9
